giltene

13 ms·

1.
by giltene 8y ago
It is an LVB (a Loaded [reference] Value Barrier), as documented and fully descibed in https://www.azul.com/files/c4_paper_acm.pdf . The Mark/Compact GC algorithm used by ZGC (see section 2 in the paper) and the LV
2.
by giltene 8y ago
If you did (dig into it yourself), you'd quickly find out that the urban myth about Zing somehow hurting latencies across the board is plain wrong. In fact, these days it tends to be percievably faster (in both latency and throughput)
3.
by giltene 9y ago
While optimization for dynamic languages is a cool research area for a JIT compiler, and may one day help expand the use of dynamic languages on the JVM, the VAST majority of code that runs on JVMs in written in Java, Scala, and Clojure,
4.
by giltene 9y ago
For actual end-user experience and impact of using Zing on AWS/Cassandra, check out: https://twitter.com/garryturk/status/859883566267871232
5.
by giltene 9y ago
I'm in no way arguing that Intel and others do not also contribute to HotSpot. It's just that MUCH more attention and seems to be paid to LLVM, and the amount and impact of contributions there are bigger. As to the AVX2 work contr
6.
by giltene 9y ago
I had actually posted an annotated assembly output for one of this example vector tests (the doAddArraysIfEven one) here: https://groups.google.com/d/msg/mechanical-sympathy/EMIBqjX4... Enjoy!
7.
by giltene 11y ago
- Zing is based on HotSpot, and it's biggest visible change is C4, but it changes a lot more than just the collector. E.g. it addresses pretty much all the causes of JVM glitches. (You can see a discussion of the many other reasons JVM
8.
by giltene 11y ago
> "...From what I've heard, Azul has a great GC, but the > throughput is extremely low. It's really only a practical > solution for high frequency finance and places like that > where latency is everything, and th
9.
by giltene 12y ago
Um. There are 30 years worth of academic publications covering concurrent compacting collectors that don't need or use transactional memory, and are implementable on commodity hardware with no emulation or specialized instructions. C4
10.
by giltene 12y ago
The 2011 C4 paper doesn't say any of the things you keep attributing to it. Just because it may also be possible to use page remapping to save on toilet paper or rescue kittens doesn't mean that's what we do with it. We do wh
11.
by giltene 12y ago
Let's see: 1. We never claimed the algorithm uses "techniques unknowable by others" (um, we published the algorithm, so it's obviously knowable by others) 2. We never claimed to have implemented generic transactional mem
12.
by giltene 12y ago
Sheesh. Read the C4 paper. See if you can point to a single place in the paper where we mention transactional memory. Or a need to invalidate an operation in the middle of some transaction. Or any form of emulation. C4 simply doesn't d
13.
by giltene 12y ago
> You're wrong. Well. One of us is wrong. I created the C4 algorithm. And I wrote the paper. I'm pretty sure I know what it does. :-) You raise another "I think this is how it works and therefore it must be slow" poin
14.
by giltene 12y ago
I don't really know where the "shitloads of money" notion comes from. I guess "shitloads" is a relative term, but Zing is usually no more expensive (and often cheaper) than the cost of the machines it runs on. Last
15.
by giltene 12y ago
While it's true that there is nothing magical in C4, pretty much everything you describe here is wrong (as in the exact opposite of what is going on). Specifically: - C4 makes no use of hardware transactional memory. - C4 works great (
16.
by giltene 12y ago
Zulu is regular OpenJDK. OpenJDK is just source code. Binaries (built by various companies and orgs) comes from someplace else, and are usually called something else. E.g. RedHat calls theirs "IcedTea". Azul calls their binary d
17.
by giltene 12y ago
Yes, there are apt repos available. Also yum repos (see links and docs at http://www.azulsystems.com/products/zulu/downloads ). On x86, if you can measure performance diffs between same-version OpenJDK/Zulu an
18.
by giltene 12y ago
Zulu is just a binary distro of OpenJDK. The other cool stuff you mention (better GC, scalability, consistent latency, etc.) is all in the Zing product line.
19.
by giltene 12y ago
Zulu is simple: It is a free and freely re-distributable binary distribution of OpenJDK for Linux, Windows, and Mac OS. Each binary is tested and certified (literally), which in the Java world is no small thing. For MacOS and Windows, Zulu